<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>基本选择器</title>
    <style>
        h1 {
            color: purple;
            background: wheat;
            border-radius: 15px;
            padding: 10px;
        }

        p {
            color: dodgerblue;
        }

        /*可以多个标签归类*/
        .title2 {
            color: red;
        }

        .title3 {
            color: brown;
        }

        #id_title3 {
            color: coral;
        }
    </style>
</head>
<body>

<h1>我是h1标签</h1>
<p>我是一个段落</p>

<h1 class="title2">我是第二个标题</h1>
<p class="title2">我是第二个段落
<div>
</p>

<h1 class="title3" id="id_title3">我是第三个标题</h1>

</body>
</html>